For diagnostic uses, the ultrasound is usually between 2 and 18 megahertz MHz. Higher frequencies provide better quality images but are more readily absorbed by the skin and other tissue, so they cannot penetrate as deeply as lower frequencies. Ultrasound will travel through blood in the heart chamber, for example, but if it hits a heart valve, it will echo, or bounce back.
It will travel straight through the gallbladder if there are no gallstones , but if there are stones, it will bounce back from them. This bouncing back, or echo, gives the ultrasound image its features. Varying shades of gray reflect different densities. Some very small transducers can be placed onto the end of a catheter and inserted into blood vessels to examine the walls of blood vessels.
Ultrasound is commonly used for diagnosis, for treatment, and for guidance during procedures such as biopsies. It can be used to examine internal organs such as the liver and kidneys, the pancreas, the thyroid gland, the testes and the ovaries, and others. An ultrasound scan can reveal whether a lump is a tumor. This could be cancerous, or a fluid-filled cyst. It can help diagnose problems with soft tissues, muscles, blood vessels, tendons, and joints.
It is used to investigate a frozen shoulder , tennis elbow , carpal tunnel syndrome , and others. Doppler ultrasound can assess the flow of blood in a vessel or blood pressure. It can determine the speed of the blood flow and any obstructions. An echocardiogram ECG is an example of Doppler ultrasound. It can be used to create images of the cardiovascular system and to measure blood flow and cardiac tissue movement at specific points. Doctors sometimes use ultrasound technology during biopsies as well.
Different types of ultrasounds serve different purposes. For example, a Doppler ultrasound is an ultrasound test that captures blood flow through the veins. An echocardiogram is an ultrasound used to diagnose a range of heart conditions and evaluate tissue damage after a heart attack. As you can see, ultrasound technology is highly versatile and useful in diagnosing, treating and monitoring a vast range of conditions.
The easiest way to remember the difference between a sonogram and an ultrasound is to keep in mind that the ultrasound is the procedure, and the sonogram is the result. One could not exist without the other. The sonogram and the ultrasound machine are both components of a highly useful medical exam. As a whole, an ultrasound and the sonogram it produces are beneficial to patients because they are:. Now that you know the difference between a sonogram and an ultrasound, are you ready for the next step?
The central processing unit measures the echo intensities and speed. The ultrasound technician uses the keyboard to enter patient data and information related to the procedure. Hard copies of the ultrasound images may be printed to present to members of the diagnostic or healthcare team. Just like the continual evolution of computers and personal communication devices, ultrasound technology continues to advance.
Originally, ultrasound technology only presented one- and two-dimensional pictures. Now there are machines capable of generating three-dimensional images. The first three-dimensional ultrasound machine dates back to the mid s; Kazunori Baba, at the University of Tokyo used this innovative technology to capture 3D images of a fetus. There are even four dimensional ultrasound machines now which generate 3D scans in real time. Ultrasound imaging uses sound waves to produce pictures of the inside of the body.
It helps diagnose the causes of pain, swelling and infection in the body's internal organs and to examine an unborn child fetus in pregnant women. In infants, doctors commonly use ultrasound to evaluate the brain, hips, and spine. It also helps guide biopsies, diagnose heart conditions, and assess damage after a heart attack.
Ultrasound is safe, noninvasive, and does not use radiation. This procedure requires little to no special preparation. Your doctor will tell you how to prepare, including whether you should not eat or drink beforehand. Leave jewelry at home and wear loose, comfortable clothing. You may need to change into a gown. Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional 3-D ultrasound that formats the sound wave data into 3-D images.
Doppler ultrasound is a special ultrasound technique that evaluates movement of materials in the body. It allows the doctor to see and evaluate blood flow through arteries and veins in the body. Ultrasound exams can help diagnose a variety of conditions and assess organ damage following illness. Ultrasound is a useful way of examining many of the body's internal organs, including but not limited to the:. With knowledge about the speed and volume of blood flow gained from a Doppler ultrasound image, the doctor can often determine whether a patient is a good candidate for a procedure like angioplasty.
Wear comfortable, loose-fitting clothing. You may need to remove all clothing and jewelry in the area to be examined. Preparation for the procedure will depend on the type of exam you will have. For some scans, your doctor may tell you not to eat or drink for up to 12 hours before your exam.
This timeframe is lower for babies and young children. For others, the doctor may ask you to drink up to six glasses of water two hours prior to your exam and avoid urinating. This will ensure your bladder is full when the scan begins. Ultrasound machines consist of a computer console, video monitor and an attached transducer. The transducer is a small hand-held device that resembles a microphone. Some exams may use different transducers with different capabilities during a single exam. The transducer sends out inaudible, high-frequency sound waves into the body and listens for the returning echoes.
The same principles apply to sonar used by boats and submarines. The technologist applies a small amount of gel to the area under examination and places the transducer there. The gel allows sound waves to travel back and forth between the transducer and the area under examination. The ultrasound image is immediately visible on a video monitor. The computer creates the image based on the loudness amplitude , pitch frequency , and time it takes for the ultrasound signal to return to the transducer.
Ultrasound imaging uses the same principles as the sonar that bats, ships, and fishermen use. When a sound wave strikes an object, it bounces back or echoes. By measuring these echo waves, it is possible to determine how far away the object is as well as its size, shape, and consistency.
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